What gets me about Fifi is that she only forgets things (as her name would suggest) - but her friends are total fuckwits.
A typical example:
Fifi: I need to get my...oh, what are they called? You drink out of them.
Bumble: Puddles?
Fifi: No! You pour juice into them!
Pip: Mouths!
Fifi: No, oh, what are they called?! They're made of glass.
Violet (with adenoidal twang): Windows!
Fifi: No, tumblers!
All: Fifi Forget-me-knot forgot!
Now, to my mind, Fifi would be well within her rights to turn to them and say "I might be forgetful, but you're just bloody idiots!"